The present invention relates to a cassette adaptor for inputting from an external equipment a signal in a recording medium other than a compact cassette tape (hereinafter referred to as "the cassette tape") used for a cassette tape reproduction apparatus mounted on the vehicle or the like.
Among the vehicle-mounted audio equipment, the cassette tape reproduction apparatus is used on many vehicles as an audio equipment as popular as a radio tuner. In recent years, with the extended use of a compact disc (CD), demand for a compact disc reproduction apparatus has increased as a vehicle-mounted sophisticated audio equipment. The compact disc reproduction apparatus, however, has so far been hard to be mounted on an automobile unless included in the standard equipment of the new automobile. Also, the compact disc reproduction apparatus is expensive as compared with the cassette tape reproduction apparatus. For these reasons, the widespread use of the compact disc reproduction apparatus for use on automotive vehicles has been hampered.
Therefore, for listening to a music etc. from a compact disc in a vehicle not equipped with a compact disc reproduction apparatus, a portable compact disc reproduction apparatus has been brought into the vehicle and connected with a cassette tape reproduction apparatus of the vehicle-mounted audio equipment for reproduction. Generally, the vehicle-mounted audio equipment has no input terminal for additional equipment, and therefore a signal output method uses a cassette adaptor as output means of a signal from the compact disc reproduction apparatus to the vehicle-mounted audio equipment. In this signal output method using a cassette adaptor, the output signal from the compact disc reproduction apparatus is input to the cassette adaptor constituting a cassette-type output unit. And this cassette adaptor has been inserted into a cassette tape insertion hole of the cassette tape reproduction apparatus constituting a vehicle-mounted audio equipment. As a result, the output signal of the portable compact disc reproduction apparatus has been input to the vehicle-mounted audio equipment through the cassette adaptor.
The prior art described above includes a method disclosed in a Japanese Patent Publication, Examined Published Patent Application HEI-4-56391.
FIG. 14 is a plan view of the conventional cassette adaptor disclosed in the Japanese Patent Publication, Examined Published Patent Application HEI-4-56391. A housing 112 of a cassette adaptor 110 shown in FIG. 14 has substantially the same shape as a housing (cassette case) of the cassette tape. In an opening 126 in the front (the lower surface in FIG. 14) of this cassette housing 112, 2-channel magnetic heads 140 are provided. A two-wire cable 142 is led out of a notch 146 of the housing 112. An end of this cable 142 is connected to an audio circuit in the housing 112, and the other end of the cable 142 has a plug 144. This plug 144 is configured to be connected to a headphone jack for a compact disc reproduction apparatus not shown. FIG. 15 is an electrical circuit diagram showing an audio circuit disposed in the housing 112.
When listening to a music or the like in the vehicle from the compact disc using the conventional cassette adaptor 110 configured as described above, the plug 144 at the other end of the cable 142 is connected to the headphone jack of the compact disc reproduction apparatus. Next, the cassette adaptor 110 is inserted into the cassette tape insertion hole of the cassette tape reproduction apparatus mounted on the vehicle. The magnetic head 140 of the cassette adaptor 110 mounted in the cassette insertion hole is in opposed relationship to the reproduction head of the cassette reproduction apparatus. Under this condition, assume that the compact disc reproduction apparatus is set in reproduction mode. The output signal of the compact disc reproduction apparatus is input to the audio circuit shown in FIG. 15 through the cable 142, and sent into the magnetic head 140. In view of the fact that the magnetic head 140 is in opposed relationship to the reproduction head of the cassette tape reproduction apparatus, the signal input to the magnetic head 140 leaks and is transmitted t o the reproduction head of the cassette tape reproduction apparatus.
In the case of reproducing a compact disc using a conventional cassette adaptor configured as described above, a signal is transmitted most efficiently when the head gap is smallest between the magnetic head of the cassette adaptor for outputting the signal and the reproduction head of the cassette tape reproduction apparatus for receiving the particular signal. In the case where the centers of the two heads are displaced from each other along the tape running direction, however, the signal transmission efficiency is greatly degraded. Also, in the case where the heights of the two head cores of the two heads for determining a transverse position of the track on which the tape runs are coincident with each other, the problems are posed that not only the signal transmission efficiency is reduced but also, for example, the reproduced sound from the left channel crosstalks with the right channel when the magnetic head on the transmission side of the left channel approaches the reproduction head of the right channel.
An ordinary cassette tape reproduction apparatus including a vehicle-mounted cassette tape reproduction apparatus has a rotation detector for detecting the rotational operation of the reels and a tape detector for detecting the presence of a tape. The rotation detector and the tape detector are provided for the purpose of preventing such an accident that a magnetic tape of a mounted cassette tape is kept in active state even when the magnetic tape is broken or a tape has twined around a rotational member, such as a capstan, due to the abnormal tape run and the cassette tape cannot be unloaded. A cassette tape reproduction apparatus having such detectors judges that the tape is broken when the reels stop rotating or the tape is out of position, and thus automatically stops or automatically unloads the cassette tape. In the conventional cassette adaptor, in order to prevent the apparatus from being automatically stopped or the cassette tape from being automatically unloaded in such a situation, various attempts have been made to keep the tape reels in rotation or to brake the tape reels to show that the tape reels are not rotating under no load.
A cassette tape reproduction apparatus including a vehicle-mounted cassette tape reproduction apparatus often employs an auto reverse mechanism. This auto reverse mechanism is so configured that when the tape being reproduced on one track reaches an end and becomes unable to continue to run in the same direction, the tape running direction is reversed to continue the reproduction along the other track. In a cassette tape reproduction apparatus having such an auto reverse mechanism, a 4-track head, for example, is used as a reproduction head, so that the lower two tracks are used for reproduction in one way while the upper two tracks are used for reproduction in the other way.
Another conventional cassette tape reproduction apparatus uses a 2-track head as a reproduction head, in which upon detection of a tape end, the cassette tape reproduction apparatus makes a half rotation to move the head cores to position on a track for reversing. When a cassette adaptor is constructed to correspond to a cassette tape reproduction apparatus having such an auto reverse mechanism, it is necessary to use a 4-track head as the magnetic head of the cassette adaptor or to use a mechanism for reversing a 2-track magnetic head. The use of a 4-track head as the magnetic head of the cassette adaptor, however, poses the problem of an increased cost of the cassette adaptor. On the other hand, provision of a mechanism for reversing the head in the cassette adaptor is virtually impossible. Therefore, most of the conventional cassette adaptors use a magnetic head having a 2-track head core. As a result, when a cassette adaptor is inserted in the conventional cassette tape reproduction apparatus, the track position of the reproduction head sometimes fails to be coincident with the track position of the signal-output magnetic head of the cassette adaptor because of different tape running directions or directions in which the cassette adaptor is mounted. In such a case, the signal cannot be transmitted from the signal-output magnetic head of the cassette adaptor to the reproduction head of the cassette tape reproduction apparatus, and therefore any sound such as a music is not output from the speaker connected to the cassette tape reproduction apparatus. The fact that no sound or the like is heard from the speaker in spite of the cassette tape reproduction apparatus being in reproduction mode often leads to the undesirable judgement that the cassette adaptor is malfunctioning.
An object of the present invention is to solve the problems of the conventional cassette adaptor and to provide a cassette adaptor capable of automatically adjusting the position of the signal-transmission magnetic head in accordance with the tape running position of the reproduction head of the cassette tape reproduction apparatus.
Another object of the present invention is to provide a cassette adaptor comprising means for preventing the reels thereof from rotating under no load and capable of rotating the reels with reliability.
Still another object of the present invention is to provide a cassette adaptor used for a cassette tape reproduction apparatus comprising an auto reverse mechanism, in the case where a track for the magnetic head of the cassette adaptor is positioned is different from a track for the reproduction head of the cassette tape reproduction apparatus, the tape running direction is reversed so that the magnetic head of the cassette adaptor is positioned on the same track as the reproduction head.